Although off-label, subcutaneous (SC) antibiotic administration is not infrequent, particularly among geriatric and palliative-care patients for whom other routes of administration are difficult to establish. Subcutaneous ceftriaxone is the most frequently prescribed antibiotic and it has been approved by some local committees given its favorable pharmacological parameters and relatively low subcutaneous toxicity. Yet pharmacologic and clinical data are lacking. No study has demonstrated non-inferiority of the subcutaneous route in comparison to other parenteral routes of administration. Randomized controlled trials are needed to assess the efficacy and tolerability of subcutaneous antibiotic administration given its frequent use in an aging population.